According to the Linux Foundation, 81 percent of recruiters say that hiring workers who know the Linux operating system is a priority. Seems unlikely to us, but we’ll swallow it for the moment. We’re not sure which recruiters they’re talking to, but it wouldn’t hurt to get up to speed. “The Linux Command Line” by William Shotts Jr., $50 from nostarch.com, is the right book for that.

If you’ve been around long enough to remember the world before Windows, you’ll remember the “command line” in DOS. Command lines are wonderful. They’re lightning fast, and that early world of computing can be had again in Linux. You can do things almost instantly with just a few key strokes in Linux.